The mechanisms that cause glaucoma are not completely known, though glaucoma has been linked to abnormally high pressure in the eye, which can lead to optic nerve damage. Over time, the increased pressure can cause damage to the optic nerve, which can lead to blindness. Treatment strategies have focused on keeping the intraocular pressure down in order to preserve as much vision as possible over the remainder of the patient's life.
Pursuant to such strategies, one or more implants can be delivered into the eye for shunting fluid out of the anterior chamber in order to regulate pressure in the eye. Accurate placement of an implant in the angle of the eye can be critical for the targeted effect of reducing intraocular pressure (IOP). Placing an implant too distally into the eye, such as too distally into the supraciliary space, may leave no portion of the implant remaining in the anterior chamber. This can inhibit aqueous outflow, as the fluid will not have a direct communication with the flow target location if there is no opening to the anterior chamber.
Conversely if the implant is placed too proximally in the supraciliary space such that a significant portion of the implant remains in the anterior chamber, damage to the corneal endothelium may result from implants that protrude upwards and touch the cornea. Implants placed too proximally may also touch the iris resulting in increased amounts of pigment dispersion in the eye, which can increase outflow resistance and intraocular pressure by clogging the trabecular meshwork. Therefore, correct placement of the implant is desired for a safe and a successful surgical outcome.
Additionally, in at least some instances, reduction in IOP can be correlated with forming one or more areas of separation between parts of the eye, such as between the choroid and sclera. These areas of separation can at least assist in allowing fluid to flow from the anterior chamber of the eye to the suprachoroidal space or supraciliary space. However, although creating separation between parts of the eye may be beneficial, creating larger incisions in the eye is generally not. For instance, a larger diameter implant may be able to create greater separation between parts of the eye, such as between the sclera and choroid, but a larger incision would be necessary which can result in excess tissue damage to the eye.